#include <bits/stdc++.h>
using namespace std;

#define fopen                                   \
    freopen("E:/vscode/oi/in.txt", "r", stdin); \
    freopen("E:/vscode/oi/out.txt", "w", stdout);
#define ios                  \
    ios::sync_with_stdio(0); \
    cin.tie(0);

#define i64 long long
#define ull unsigned i64
#define pii pair<int, int>
#define pdd pair<double, double>
#define ld long double
#define ls(x) (x << 1)
#define rs(x) (x << 1 | 1)
#define lowbit(x) (x & -x)
#define de(x) cout << #x << " = " << x << '\n'
#define MAXP 20

const int N = 1e5 + 10, M = 1e2 + 10;
const double eps = 1e-12;
const double PI = acos(-1);

bool Mst;
vector<pii> vec;
vector<int> ans;
int n, m, k, d;
void calc(int l, int r, int lim)
{
    int len = vec[r].first - vec[l].first + 1, cnt = (len + d - 1) / d;
    int delta = cnt * d - len;
    int st = max(lim, vec[l].first - delta);
    for (int i = 0; i < cnt; i++)
        ans.push_back(st + i * d);
}

bool go(int l, int r)
{
    int lim = vec[l].first + 1;
    for (int i = l + 1; i < r; i++)
    {
        int ql = vec[i].first;
        int j = i;
        while (j + 1 < r && vec[j + 1].first - vec[j].first < d)
            ++j;
        calc(i, j, lim);
        lim = ans.back() + d;
        i = j;
    }
    if (lim > vec[r].first)
        return false;
    return true;
}

void solve()
{
    cin >> n >> m >> d >> k;
    vec.clear();
    ans.clear();
    for (int i = 0, x; i < n; i++)
    {
        cin >> x;
        vec.push_back({x, 0});
    }
    for (int i = 0, x; i < m; i++)
    {
        cin >> x;
        vec.push_back({x, 1});
    }
    vec.push_back({0, 1});
    vec.push_back({k + 1, 1});
    sort(vec.begin(), vec.end());
    for (int i = 1; i <= n + m; i++)
        if (vec[i - 1].second == 1 && vec[i].second == 0)
        {
            int j = i;
            while (vec[j].second == 0)
                ++j;
            if (!go(i - 1, j))
            {
                cout << -1 << '\n';
                return;
            }
            i = j;
        }
    cout << ans.size() << '\n';
    for (int x : ans)
        cout << x << ' ';
    cout << '\n';
}

bool Med;

signed main()
{
    ios;
    // fopen;
    cerr << (&Med - &Mst) / 1024 / 1024;

    int t = 1;
    srand(time(0));
    cout << fixed << setprecision(12);

    cin >> t;
    for (int i = 1; i <= t; i++)
    {
        solve();
    }

    return 0;
}